config

Documentation

Overview

Package config provides decoupling between various configuration sources (etcd, files,...) and the pieces that actually care about them (loadbalancer, proxy). Config takes 1 or more configuration sources and allows for incremental (add/remove) and full replace (set) changes from each of the sources, then creates a union of the configuration and provides a unified view for both service handlers as well as endpoint handlers. There is no attempt to resolve conflicts of any sort. Basic idea is that each configuration source gets a channel from the Config service and pushes updates to it via that channel. Config then keeps track of incremental & replace changes and distributes them to listeners as appropriate.

Index

• type ConfigSourceEtcd
  • func NewConfigSourceEtcd(client *etcd.Client, serviceChannel chan ServiceUpdate, ...) ConfigSourceEtcd
  • func (s ConfigSourceEtcd) GetEndpoints(service string) (api.Endpoints, error)
  • func (s ConfigSourceEtcd) GetServices() ([]api.Service, []api.Endpoints, error)
  • func (s ConfigSourceEtcd) ProcessChange(response *etcd.Response)
  • func (s ConfigSourceEtcd) ProcessEndpointResponse(response *etcd.Response)
  • func (s ConfigSourceEtcd) Run()
  • func (s ConfigSourceEtcd) WatchForChanges()
• type ConfigSourceFile
  • func NewConfigSourceFile(filename string, serviceChannel chan ServiceUpdate, ...) ConfigSourceFile
  • func (s ConfigSourceFile) Run()
• type EndpointsConfig
  • func NewEndpointsConfig() *EndpointsConfig
  • func (c *EndpointsConfig) Channel(source string) chan EndpointsUpdate
  • func (c *EndpointsConfig) Config() map[string]map[string]api.Endpoints
  • func (c *EndpointsConfig) RegisterHandler(handler EndpointsConfigHandler)
• type EndpointsConfigHandler
• type EndpointsUpdate
• type Operation
• type ServiceConfig
  • func NewServiceConfig() *ServiceConfig
  • func (c *ServiceConfig) Channel(source string) chan ServiceUpdate
  • func (c *ServiceConfig) Config() map[string]map[string]api.Service
  • func (c *ServiceConfig) RegisterHandler(handler ServiceConfigHandler)
• type ServiceConfigHandler
• type ServiceUpdate
• type SourceAPI
  • func NewSourceAPI(client Watcher, period time.Duration, services chan<- ServiceUpdate, ...) *SourceAPI
• type Watcher

Types

type ConfigSourceEtcd

type ConfigSourceEtcd struct {
	// contains filtered or unexported fields
}

ConfigSourceEtcd communicates with a etcd via the client, and sends the change notification of services and endpoints to the specified channels.

func NewConfigSourceEtcd

func NewConfigSourceEtcd(client *etcd.Client, serviceChannel chan ServiceUpdate, endpointsChannel chan EndpointsUpdate) ConfigSourceEtcd

NewConfigSourceEtcd creates a new ConfigSourceEtcd and immediately runs the created ConfigSourceEtcd in a goroutine.

func (ConfigSourceEtcd) GetEndpoints

func (s ConfigSourceEtcd) GetEndpoints(service string) (api.Endpoints, error)

GetEndpoints finds the list of endpoints of the service from etcd.

func (ConfigSourceEtcd) GetServices

func (s ConfigSourceEtcd) GetServices() ([]api.Service, []api.Endpoints, error)

GetServices finds the list of services and their endpoints from etcd. This operation is akin to a set a known good at regular intervals.

func (ConfigSourceEtcd) ProcessChange

func (s ConfigSourceEtcd) ProcessChange(response *etcd.Response)

func (ConfigSourceEtcd) ProcessEndpointResponse

func (s ConfigSourceEtcd) ProcessEndpointResponse(response *etcd.Response)

func (ConfigSourceEtcd) Run

func (s ConfigSourceEtcd) Run()

Run begins watching for new services and their endpoints on etcd.

func (ConfigSourceEtcd) WatchForChanges

func (s ConfigSourceEtcd) WatchForChanges()

type ConfigSourceFile

type ConfigSourceFile struct {
	// contains filtered or unexported fields
}

ConfigSourceFile periodically reads service configurations in JSON from a file, and sends the services and endpoints defined in the file to the specified channels.

func NewConfigSourceFile

func NewConfigSourceFile(filename string, serviceChannel chan ServiceUpdate, endpointsChannel chan EndpointsUpdate) ConfigSourceFile

NewConfigSourceFile creates a new ConfigSourceFile and let it immediately runs the created ConfigSourceFile in a goroutine.

func (ConfigSourceFile) Run

func (s ConfigSourceFile) Run()

Run begins watching the config file.

type EndpointsConfig

type EndpointsConfig struct {
	// contains filtered or unexported fields
}

EndpointsConfig tracks a set of endpoints configurations. It accepts "set", "add" and "remove" operations of endpoints via channels, and invokes registered handlers on change.

func NewEndpointsConfig

func NewEndpointsConfig() *EndpointsConfig

NewEndpointConfig creates a new EndpointConfig. It immediately runs the created EndpointConfig.

func (*EndpointsConfig) Channel

func (c *EndpointsConfig) Channel(source string) chan EndpointsUpdate

func (*EndpointsConfig) Config

func (c *EndpointsConfig) Config() map[string]map[string]api.Endpoints

func (*EndpointsConfig) RegisterHandler

func (c *EndpointsConfig) RegisterHandler(handler EndpointsConfigHandler)

type EndpointsConfigHandler

type EndpointsConfigHandler interface {
	// OnUpdate gets called when endpoints configuration is changed for a given
	// service on any of the configuration sources. An example is when a new
	// service comes up, or when containers come up or down for an existing service.
	OnUpdate(endpoints []api.Endpoints)
}

EndpointsConfigHandler is an abstract interface of objects which receive update notifications for the set of endpoints.

type EndpointsUpdate

type EndpointsUpdate struct {
	Endpoints []api.Endpoints
	Op        Operation
}

EndpointsUpdate describes an operation of endpoints, sent on the channel. You can add or remove single endpoints by sending an array of size one and Op == ADD|REMOVE. For setting the state of the system to a given state for this source configuration, set Endpoints as desired and Op to SET, which will reset the system state to that specified in this operation for this source channel. To remove all endpoints, set Endpoints to empty array and Op to SET

type Operation

type Operation int

Operation is a type of operation of services or endpoints.

const (
	SET Operation = iota
	ADD
	REMOVE
)

These are the available operation types.

type ServiceConfig

type ServiceConfig struct {
	// contains filtered or unexported fields
}

ServiceConfig tracks a set of service configurations. It accepts "set", "add" and "remove" operations of services via channels, and invokes registered handlers on change.

func NewServiceConfig

func NewServiceConfig() *ServiceConfig

NewServiceConfig creates a new ServiceConfig. It immediately runs the created ServiceConfig.

func (*ServiceConfig) Channel

func (c *ServiceConfig) Channel(source string) chan ServiceUpdate

func (*ServiceConfig) Config

func (c *ServiceConfig) Config() map[string]map[string]api.Service

func (*ServiceConfig) RegisterHandler

func (c *ServiceConfig) RegisterHandler(handler ServiceConfigHandler)

type ServiceConfigHandler

type ServiceConfigHandler interface {
	// OnUpdate gets called when a configuration has been changed by one of the sources.
	// This is the union of all the configuration sources.
	OnUpdate(services []api.Service)
}

ServiceConfigHandler is an abstract interface of objects which receive update notifications for the set of services.

type ServiceUpdate

type ServiceUpdate struct {
	Services []api.Service
	Op       Operation
}

ServiceUpdate describes an operation of services, sent on the channel. You can add or remove single services by sending an array of size one and Op == ADD|REMOVE. For setting the state of the system to a given state for this source configuration, set Services as desired and Op to SET, which will reset the system state to that specified in this operation for this source channel. To remove all services, set Services to empty array and Op to SET

type SourceAPI

type SourceAPI struct {
	// contains filtered or unexported fields
}

SourceAPI implements a configuration source for services and endpoints that uses the client watch API to efficiently detect changes.

func NewSourceAPI

func NewSourceAPI(client Watcher, period time.Duration, services chan<- ServiceUpdate, endpoints chan<- EndpointsUpdate) *SourceAPI

NewSourceAPI creates a config source that watches for changes to the services and endpoints

type Watcher

type Watcher interface {
	WatchServices(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error)
	WatchEndpoints(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error)
}

Watcher is the interface needed to receive changes to services and endpoints